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How are insects and arachnids kept out of commercial passenger airliners?
If a commercial passenger airliner were to land in a place infested with insects or arachnids, wouldn't it be dangerous to have those animals enter the aircraft?
For example, suppose if mosquitoes, bees, or spiders were to enter the cockpit, wouldn't that be a huge distraction for the pilots? Wouldn't that potentially compromise the safety of the passengers?
The main questions are:

Are there established methods/protocols/regulations for ridding aircraft of potentially dangerous insects?
If so, what are they?

(Note: I am new to all of this. A thought occurred to me that mosquitoes onboard aircraft could potentially endanger the passengers onboard).

In 44 years of flying I have never heard of this being a problem. You keep doors and hatches closed when they don't need to be open and if necessary you go through the cockpit and cabin to check if necessary.

Insects can be a problem, see this question.

@JuanJimenez surely you have heard of https://en.wikipedia.org/wiki/Birgenair_Flight_301 ? the op's question might be narrow if its list of potential problems, but insect absolutely are an issue.

@AEhere That link is irrelevant to your question. The wasps in that case entered the pitot tube and not the cabin or cockpit, because the pitot covers were not installed while the aircraft sat on the ramp for two days. An airliner's pitot-static system doesn't vent into the cabin or cockpit -- the exit points are the static ports on the outside. Perhaps you want to edit the question to take that into consideration.

Like anywhere else, they only become a problem if they affect safety. That is why things like pitot probes and static ports are covered to prevent insects like  mud-daubers' from building their homes inside. Depending on the area it could only apply if the aircraft is not flying for x amount of time but in areas where these insects are very active it could be required for shorter transits. The recent Malaysia Airlines case (Brisbane, Aust) where the pitot-cover was not removed before flight was a case where the covers were place for a short transit because of these insect activity.
If the destination country has laws in place where the entry of non local insects is not tolerated they may require the airline to spray the holds before departure. I remember doing this for flights to Australia. We had cans with a 'lock' trigger (continues to spray without finger pressure) which we would activate and leave in the holds before closing the doors. It was important to notify the crews beforehand as the mist could activate the smoke detectors.

Insects aren't the main problem. A few mosquitoes aren't a major safety hazard, and it's hard to miss a beehive in your plane. The main issue are rodents like mice, snakes and lizards. Rats and mice are particularly known to chew on wires, an issue commonly faced in cars.
The main prevention is to close all doors and hatches as soon as possible after use and to ensure galleys are emptied and the aircraft clean of food after landing.
However, when there is an infestation, the aircraft can be sealed and fumigated. Airbus has a fumigation procedure in the AMM using methyl bromide or CO2. The procedure is actually easier than fumigating a house since aircraft are naturally airtight. A special fitting over the outflow valve is used and a specified volume of the gas is pumped in. The aircraft sits, and then is ventilated.


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Is the cargo door on this airplane really malfunctioning?
Recently, I saw that video:
EDIT: I removed the Facebook video link which would require sign up for anyone without an account. I've re-uploaded the video here:
https://vid.me/8WYI
In general, this guy's videos seem to me more like a "conspiracy theories" thing, but I hadn't the time to study them and find the underlying faulty logic. So, in that particular video, he claims that the cargo door of an aircraft wasn't working properly and the ground staff simply decided to use a heavy load on the lever in order to open it (or something like that).
Because of that incident the plane shouldn't be allowed to fly (that's what he claims) and also there is immediate safety concern for the people on the ground because of the weight they used.
My questions are:

Is the cargo door in that airplane really malfunctioning?
Do the ground staff follow a standard procedure for the "workaround"?
Although I understand that the way the weight is "hanged" on the that
lever is not a safe solution, my logic says that it could never fall
from that position. Am I right?

Link does not lead to a video. It leads to an invitation to join facebook in order to learn all about some anti-journalist called Oskar T. Brand.

@A.I.Breveleri You're right. I will try to find another source for the video and update my question ASAP.

Some people who don't know much about aviation think that the slightest problem on a plane - like a sticky handle - means it shouldn't fly. They would be terrorfied to learn of the amount of items that are legally allowed to not work properly and still carry passengers.

@Ben -- yeah, they're the folks who need a MMEL dropped on their heads :P

meh... I was going to include the YouTube link as well, but he doesn't even have this posted on YT. Based on the videos he does have there, with titles like Marihuana Truth: 420 Trillion Dead, I'd not put much credibility in anything this guy says. Honestly, if he said I needed to breath air to continue living, I'd question it.

It appears as though the locking handle for the door has some sort of switch in it to allow for full extension of the door only if the locking handle is pulled full forward and, for whatever reason, the door handle won't move into this fully extended detent on its own.  While the workaround is jury rigged at best, it doesn't seem to pose a flight safety issue unless the door can't be locked when fully closed.  It's just another video from an ignoramus in the terminal with a cellphone camera.

So, even though this might not be an actual problem, it can't be proven by what we see here. And this guy's video could easily mislead other people without knowledge on aviation/engineering, right?

I like how he writes, "Ready to take off" when they are clearly UNloading the cargo.

He acknowledges that he's "No aviation expert", yet he's spreading FUD with the best of them. Actually, that's exactly where the FUD comes from - non experts. :(

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Is it feasible to replace brakes on airplanes with electric motor/generator?
Would it be feasible to replace the brakes on airplanes with electric motor/generator drive systems?
There are two problems I see with airplanes. When they land, the tires are not spinning to match the ground speed, as the craft touches the ground. So there is a sudden lurch as the tires touch the ground and suddenly begin spinning. The bigger the craft, the more tire mass that must be instantly accelerated.
This disrupts flight stability, and the jolt could be enough to cause a crash or mishap in poor landing conditions. It also causes unnecessary wear and stress to the tires due to the motionless rubber dragging across the runway pavement at first contact.
It would be best for the tires to be spun up to match the ground speed before the craft touches the ground, for the smoothest landing possible.

The second part is just simply the problem of dissipation of heat. It has been discussed elsewhere here that the heat from braking can cause fires and crashes.
As in train locomotives, with a braking motor/generator, the heat could potentially be moved elsewhere to resistive heat coils covering a large area, and cooled using forward thrust or fans.

With a motor/generator unit, the tires can be spun up to either near or matching ground speed, using them as motors powered by the APU, and then switched to be used as generators for braking after ground contact is made.
Has this ever been researched or used on airplanes?
(As a lower middle-class American that is not involved in the airplane industry, I have no hope of doing anything with this or profiting from it, even if it is a practical and potentially patentable new concept that has never been tried before.)
EDIT

I am not talking about regenerative braking or energy recovery into a storage battery. Someone has inferred that though I didn't say anything about it at all.
I understand the storage battery would likely be too much extra weight for a plane to carry, vs the energy recovery of takeoff and landing. (Heh, have a 2000 ft breakaway extension cord on a reel, to drive it down the runway and disconnect right before it lifts off the ground.)
I am only looking at resistive / dynamic braking, dumping the heat in huge resistor banks with a high speed blower, the same as is used on train locomotives. On a plane, air bleed from the engines can blow across the the resistor banks.
Probably should pluralize the title. Rather than a single huge motor/generator, each brake assembly would be replaced by a separate one of these.
So a large plane with say 20 wheels would have 20 motor/generator units, these running at high voltage to keep the amps and wire diameter small. This reduces weight and engineering complexity, eliminating gears and shafts linking all wheels on one set of gear, to one huge motor/gen unit.
This is not two separate devices, but one device that does both functions. Most (but not all) generic electric motors without electronic drive systems can also be a generator.
This could use a permanent magnet motor, or with a powered field coil. Neodymium is capable of extremely high flux density, but loses it when exposed to high heat, so there are density / temperature tradeoffs of permanent vs powered field coils.
Tire hub could potentially be integrated as part of the motor/gen rotor/casing for weight savings (which is very important in aircraft), using a fixed core and a hub that rotates around it in reverse of conventional motor design.

Hi Dale, welcome! I suggest you split the question into two. Spinning the wheels has been answered in Why are aircraft tires not pre-spun prior to landing to preserve them? and How long do airliner tires last? Can this be improved? and also in How are forces on the landing gear reduced or compensated for at touchdown?, so better to remove it from this question.

Regarding the second part "then switched to be used as generators for braking after ground contact is made". It's a good question, and I wonder how we could use this 1GJ work.

Small note: I suspect that the "lurch" from getting the tires spinning at touch-down is next to zero, and that the real lurch comes from the non-zero vertical and lateral acceleration due to contact with the runway.

@Dale_Mahalko: "I understand the storage battery would likely be too much extra weight for a plane to carry, vs the energy recovery of takeoff and landing."  Airplanes already have some pretty big batteries; it probably wouldn't be too much trouble to connect the mogens up to that.

On a hybrid or all-electric car, the motors on the wheels supplement or replace the engine, and by regenerating electricity from the braking, it extends the range of the battery.
On an aircraft, the engines would still be needed for the major part of the working life of the aircraft -- the time while it is in flight.  So unlike the case of a car, you don't get any advantage with the motors themselves by adding the motor/generators to the wheels.
Beyond this, on a large aircraft, electricity is in ample supply when you have jet engines turning, so what's gained by regenerating the electricity from the wheels, during the 60-90 seconds of heavy braking on landing, isn't all that significant when compared to the electricity used and produced over the course of a whole flight.  Not nearly as significant as a drive in the city with many cycles of accellerating to speed then decelerating to a stop, over and over.
Beyond this, the major players then are the added weight and complexity of the motor/generators, vs the gains in terms of (a) tire life, from spinning them up prior to landing, and (b) fuel saved by maneuvering on the ground from the wheel motors instead of the jet engines.  When you consider that the costs of jet fuel are on the order of $1000 to multi-thousands of dollars per flight hour, the costs savings of longer tire life will lose out if the extra weight of the motor generators over conventional brakes means that you're spending more money over the course of the flight to carry the extra weight.  Likewise, the fuel burn during taxi in & taxi our on the motors isn't all that great compared to an hour or many of high-power cruise... power settings for taxi are close to or at idle, so fuel consumption isn't all that high.  Plus, it's common to taxi without all engines running, further reducing fuel burn on the ground.
The big killer for this idea is the weight penalty.  Motor generators are significantly heavier than conventional brakes, and when you consider the amount of energy that brakes have to be able to absorb during a high-speed stop, you'd need some seriously beefy generators to accomplish what aircraft brakes can do.  Or else, you'd have conventional brakes installed to supplement the generators, and the weight goes up further.
As a ballpark, on an hour flight in a 737, an extra 1000 lbs of weight increases the fuel burn by about 10 lbs, or about 1.5 gallons.  Doesn't sound like much, but when you multiply the added weight times every flight hour that the aircraft is operated over the course of a year, it really adds up.  Beyond that, motor/generators are a lot more complex than simple brakes, so they'd be more expensive initially and require more maintenance throughout their service life.  Plus, I suspect, they'd need to be supplemented by conventional brakes that would be used in the event of a high-speed max-effort stop (rejected takeoff, landing on a short runway).
The end result of all of this is, no manufacturer I'm aware of has found that the tradeoffs make this sort of project worthwhile.
The best case is probably one of really long taxi times, but in that case a pushback tug could tow the aircraft to a point close to the runway, saving the fuel burn on the aircraft engines until it was time to start them.  I'm sure this has been considered as well, and again, I'm not aware of any carrier that uses this approach (although outside the U.S., somebody might be).
It's an interesting question, but the costs & the math behind the engineering haven't worked out in its favor, at least thus far.

Just dumping the power to resistor banks might be useful because the energy is no longer concentrated right next to the wheels.

Feasible? Maybe. Sensible? Clearly no.
Let's first look at the energies involved: Braking a Boeing 747 to a complete stop will change its kinetic energy by 276.4 kWh. Drag and friction will maybe swallow 20% of that, so we have 221 kWh or 795.6 MJ to convert to electricity within 30 seconds. This means the generators have to be sized for a load of 26.5 MW. If you can live with a longer deceleration distance, the generator has more time to apply its drag and can be smaller for the same overall stopping power, but it will be hard to make your prospective pilots accept that your design will now need a much longer runway.
I found it hard to find online sources for the mass of aviation generators, and the best so far was Jan's answer here and this EAA page. It seems a lightweight starter/generator could have 5kW of power per kg of mass, so the 26.5 MW generator should weigh 5.3 tons.
Next would be energy storage: In order to keep the recuperated energy for taxiing and the next take-off run, the battery will need to weigh 800 kg (assuming 1 kg of battery mass per MJ of stored energy). Of course, the efficiency of the generator and the DC converter will be below 100%, so maybe the battery can be a little lighter. A 70% overall efficiency will only require 560 kg for the battery.
How much brake mass and fuel would that save? Again, aircraft brake masses are hard to find online, and I did not want to go through a proper disc brake sizing. But I bet it is a small fraction of the generator mass - maybe 10%! With 43 MJ/kg and maybe a quarter of the efficiency of electric wheel motors, the fuel needed is just 75 kg. Here I assumed we are feeding 800 MJ to the wheel motors and try to achieve an equivalent acceleration with conventional jet engines. Now consider that this fuel is no longer burdening the aircraft for the remainder of its trip while the batteries and generators still need to be carried around.
So it looks like the conventional solution has 10% of the mass of a proper generator brake and needs just 75 kg of fuel even for the biggest airliners. Carrying the generator and battery around will use much more fuel or require our hypothetical 747 to carry 61 passengers less. No airline can accept that!
Regarding the wheel spin-up on touch down you say:

This disrupts flight stability, and the jolt could be enough to cause
  a crash or mishap in poor landing conditions. It also causes
  unnecessary wear and stress to the tires due to the motionless rubber

Yes, spin-up causes some of the rubber to burn away (just watch any airliner landing - spin-up is signalled by a cloud of smoke, and skid marks on the runway) but I would not worry about flight stability once the aircraft is down on the ground. Even locked wheel brakes are not a real danger to flight safety on modern tricycle gears.

I'm not sure how to read the information here. But a lightweight 10 MW (10 MJ/s) alternator could weight about 160 tons when not using supra-conductivity.

@mins: You read right, but this is for stationary applications which must never, ever fail and is slowly spinning (that is why those wind power people accept geared generators). The RPM on a wheel is much higher, so the generator can be smaller and lighter. But I certainly picked a very optimistic value.

Can't see mentioned in the thread another issue would be aquaplaning on a wet runway. It is better to land hard and let the skidding tyres break through the water film on the runway. The tyres would be delayed in making contact with the runway in wet weather if they were sped up before touchdown.

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How is the chord length defined if the wing (whale flipper) is tapering like a wing and has a twist throughout the span?
Let me be more specific:

I have a 3D scan of a whale tubercle.
The tubercle is tapering and twisting along its half span.
I want to find the mean chord length.

Now let us say that my airfoil section is at 10 degrees. So how is the chord length defined?

a) is it a line that directly joins the LE and the TE (chord length has a slant)
b) is it the line joining the projection of the LE and TE on a flat plane ( slope of chord line =0)

Which f̶l̶a̶t̶ (every plane is flat) plane would you want to use? The aircraft reference datum is rather arbitrary and the relative wind changes with speed and wing loading.

Just added a picture in the question... so up here in the picture, the chord length is defined as 'a straight line joining the LE to TE' but book claim it to be 'the chord is simply the size of the wing in streamwise direction'

I don't think it is a duplicate because the referenced question doesn't answer how to deal with variable twist when calculating the mean chord ("3. I want to find the mean chord length"). The question "Is $S=\int c(y) dx$ or is it the projected surface on a certain plane ($S=\int c(y)\cdot cos(\alpha_i(y)) dx$, with $\alpha_i$ the incidence angle)?" isn't answered there. @AdityaKulkarni You'll probably have to pick a definition yourself. I'd choose a plane which minimizes incidence angles along the span and calculate the projected surface on it. For the mean chord $MC=\frac{S}{Span}$.


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Where can Cirrus Aircraft VisionJet Oleo Struts Material and Dimension Specifications be found?
I am looking to get hold of Cirrus Aircraft VisionJet Oleo Struts Material and Dimension Specifications. Can anyone point me to or share where I can obtain these details. So far, I have been able to get general specifications at the following link.
https://cirrusaircraft.com/aircraft/vision-jet
Thanks.
Vedanth

You're after the landing gear oleo Source Control Drawings.  You need to contact Cirrus' tech support and request the drawings from their engineering organization via their support organization, who may or may not want to help you, or may charge for them if they do.
I expect they won't want to provide them because they'll suspect that it's for someone who wants to make a PMA (Parts Manufacturer Approval) copy. It's usually pretty tough to find source documentation like that for a product that is in current production.

Thanks. I really do not want the detailed info.. which I agree they may not provide. Would you be aware on details of the above mentioned aircraft or others of similar type.. Details such as length of 1) Oleo strut length, 2) Oleo stroke length, 3) Oleo diameter , 4) Oleo strut Operating temparature (min/max). I am not looking for accuratedetails. Even  general approximate information  should do.Thx.

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How to Tell Flight Following You Want to Change Your Destination?
I want to fly the LAX Coastal VFR Transition Route northbound, and I want to do the whole thing with flight following.  When I get near Van Nuys airport, I'll need to tell ATC (flight following) that I want to change my direction and head eastward to a different airport.  How do I do this?  And more broadly, how do I tell flight following radar services that I want to change my destination?  For some routes it seems easier for me to have them follow me with radar services to a certain airport that I don't intend to land at, then ask them to change as I fly to a different airport.

Don't give them a fake destination. That is bound to cause issues somewhere in the system.

Just tell them.  Like you told us in the question.  Seriously, plain old English works just fine on the radio.
Don't get all chatty, and be professional, but don't overthink things and feel you need to use a bunch of radiotelephony code words to get a simple point across.
The most important thing is to clearly communicate intentions.  Don't tell them you are going one place and then "change" it when you actually planned on going there all along.  That's phony and unnecessary, and could confuse things if there any sort of emergency where knowing your planned route of flight or destination would be useful.
Simply tell them you plan to fly VFR up the coast to VanNuys, then turn Eastward and proceed to destination XYZ.  Or, more briefly:  "destination XYZ, via Van Nuys".  It's just that simple.
And consider filing a flight plan.

If you need to unexpectedly change your destination, the correct phraseology would be "Facility, Cessna 12345, amend destination XYZ." They may ask you why, so have a concise explanation ready; "comfort" works for anything biological, such as needing a potty break, food or a break to stretch your legs. "Fuel" or "weather" are also common reasons. They don't really care what you say unless it sounds like an emergency (or may soon become one).
However, you should never plan to use this. If your route is within about 30° of direct, just fly what you want; ATC expects VFR flights to wander somewhat. If it's less direct than that, in your initial request use "via" the airport or navaid nearest where you plan to turn. So, rather than tell them you're flying to ABC and then amending to XYZ when you get close, just say you're flying to XYZ via ABC; it's easier on both you and them.

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Why does the Embraer E-Jet Family have doors of different sizes?
I just noticed yesterday that the right and left forward doors of all E-Jet Family aircraft have different sizes (both in height and in width). What is the reason behind this design difference?

Where does you picture come from?

What's the point of having the same size?

@ManuH the first picture: https://www.flyembraer.com/irj/go/km/docs/download_center/Anonymous/Ergonomia/Home%20Page/Documents/APM_190.pdf (page 41), the second picture: https://www.flickr.com/photos/craignos/5521379897/lightbox/

It's actually more common than one might expect, and not just in the E-jet family.
The de-facto standard is that passengers board from the left and the right side doors are only used to load logistical stuff (ie catering) during the turnaround or during an emergency evacuation.
As such, the left side door(s) must fit certain FAA standards (so it fits jet bridges or the average human height, for example).
For example, on the Boeing 737 (all models), the left forward door is 0.86 x 1.83 meters while the right forward door is 0.76 x 1.65 meters, 20 percent smaller (by area).
Now you might ask "ok, so make both doors the size of the left door". It's beneficial, from engineering/structural point-of-view, to have each door as small as possible.
(http://www.boeing.com/assets/pdf/commercial/airports/acaps/737.pdf pages 73 and 77)

What benefits exist from engineering/structural point-of-view, to have each door as small as possible exactly? Just curious...

@Ja380 pressurization/structural integrity concerns.

You have two big holes in a pressure vessel at the same station.  To get away with doing that, the frames around the openings have to be reinforced, often with the doors themselves carrying some of the tension loads through the latching system's interconnection with the frame.  The smaller the opening the better, from a strength to weight perspective, so the SD is made to be as small as practical.


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What is the dutch roll filter? How does it work?
Some airplanes have a dutch roll filter for the "yaw damper."
What is the dutch roll filter?
When is it used?
Is it ever required for certification or operation?
How does it work?

you already asked a question about the difference between airbus and boeing. asking again won't help.

We don't mind people asking homework related questions, but we do expect that you do your research first and show some prior effort.

The homework assignment questions stick out like a sore thumb don't they.

It keeps particles from getting into your Dutch roll.

Nobody likes particles in their Dutch roll - ruins the taste.

Yaw damper systems implemented on most transport category aircraft accomplish the task of damping the dutch-roll. The only control output needed is the rudder.
Simple yaw damper system may use only yaw rate in its feedback. This increases the effective yaw damping, which increases the dutch-roll damping and is robust. However, the presence of the washout filter is less amenable to combating dutch-roll during turn maneuvers. In order to achieve good transient behaviour and adverse yaw suppression, feedforward is typically added from roll command in the form of turn coordination function. An example of a yaw rate damper design with feedforward is shown below:

Image ref: NASA TN D-5890
Most modern yaw damper on large transport category aircraft also feeds back lateral acceleration ($N_y$), since it's dynamically coupled with sideslip in flight, blended with yaw rate to increase robustness, and using the rudder system as the control output. This design is much more capable at suppressing undesired oscillations during turns. An example is shown below (the yaw damping system is the bottom half):

Image ref: NASA TM X-62,094
With fly-by-wire, the latitude of control is greatly expanded. Control techniques such as eigenstructure assignment can be employed to completely separate lateral/directional degrees of freedom, thereby eliminating dutch-roll altogether.

I assume you know what a dutch roll is, if not here is a brief summary:
At the airplane yaws to one side the wing that is moving forward has a higher speed and creates more lift which causes the aircraft to roll towards the trailing wing. There are also effects like the vertical stabilizer usually being above the center of gravity which at great side slip angles causes the aircraft to roll towards the trailing wing as well. And lastly there are effects like the fuselage causing a disturbance on the trailing wing.
All these effects depend on the aircraft type and wing configurations. But generally speaking a yaw rate creates a roll rate as a side effect. And if you move the rudder left and right constantly then you cause the wings to rock, which is called a dutch roll. This behavior is quite unpleasant for passengers in the back or front because they are accelerated left and right.
To suppress this side effect of a yaw motion creating a roll motion and a subsequent dutch roll you can add a "durch roll filter" to the yaw damper control system. All it does from my understanding is to combine the normal feedback loop for the yaw rate with a second loop for the roll rate. This causes the yaw damper to reduce rudder deflection slightly whenever the roll rate picks up and increases it again when the roll rate stagnates which can stabilize the dutch roll and causes a more uniform roll rate.
Modern fly by wire aircraft can also use the ailerons to dampen the dutch roll much more effectively. But if the yaw damper can only affect the rudder than this is obviously not an option.
I'm not 100% sure when it's used but I'm guessing that all modern airliners have this because there are people in the far back that would get motion sickness really quickly when the yaw damper allows a dutch roll and the aircraft swings side to side on every turn. For a small general aviation aircraft this may not be needed and development costs can be kept low.
As per all control systems I think the yaw damper with or without this filter has to be certified. And if the system is changed later on will also have to be tested and certified. Depending on the aircraft type you may need redundant yaw dampers

So , with this information , can we say these are the difference boeing and airbus for the dutch roll filter?

It's not as black and white as you may think at first. Both aircraft manufacturers probably have made many iterations of yaw damper designs over the years and I'm sure a modern B787 yaw damper or an A350 yaw damper have a lot in common and are both pretty advanced. I would argue more on a per aircraft basis rather than Airbus vs. Boeing but I don't know the individual designs they used.

Also the big manufacturers tend to out-source parts of the developments and could buy full avionics packaged, flight control systems or other things. It could even be the case that one Airbus aircraft and one Boeing aircraft have the exact same yaw damper.

as I understand it, the difference in dutch roll filter on older aircraft is related to the fly by wire system.

I've been in aviation nearly 20 years and never heard it called a dutch roll filter. It's called a yaw damper system and it is part of or related to the automatic flight control system. Doesn't have to be a fly by wire aircraft. Planes with rods and cables still can have a yaw damper to reduce dutch roll. E.g BAE Hawk 127

Yes but for a yaw damper there are different control methods. The basic yaw damper just looks at the yaw rate. This dampens the yaw motion but the Dutch roll damping can be improved still, hence an additional feedback loop

In your explanation of "Dutch Roll", no mention at all of the "positive effective dihedral" to sweep, and/or actual physical dihedral, coupling with sideslip to create a roll torque?  Surely this is an important part of the dynamics at play.  (You did mention a similar effect arising from the tall vertical fin so that's a start... )


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How do coefficient of lift/drag variation with speed differs between swept and unswept wings?
Trying to understand the coefficient of lift/drag of swept and unswept wings as speed increases.  Some example questions and statements-
A swept wing will have a lower max Cl at subsonic and supersonic speeds.  I understand the lower max cl at subsonic, but the lower max cl at supersonic has confused me?
When the speed increases for a swept wing from subsonic to supersonic Mach numbers, the max CL is more or less?
CL is more at supersonic and less for subsonic.
Comparing swept and unswept wings as angle of attack is increased the swept wing will produce less lift(this i understand) and more drag.  Why more drag?  Is it due to the span wise flow being greater?

related: Why is the coefficient of drag for straight wings at supersonic speeds lower than for swept wings?

It's not so simple.
For swept wings it is essential whether the leading edge is sub- or supersonic.
What does that mean?
If the leading edge is within the Mach cone emanating from the tip of the wing, it is called subsonic. The approaching air will "sense" what is coming and behave much like in subsonic flow. This keeps nose suction alive; an effect that can be maximized by the use of conical camber: Here, the leading edge is bent down similar to a cone surface with its apex at the wing root and the cambered part increasing towards the wing tip. This forward-facing part of the wing experiences suction which helps to pull the airplane forward.

Conical camber on the wing of the SR-71 (own work)
Of course, such a swept wing with a subsonic leading edge will also stall quite like it does at subsonic speed. However, the drag caused by a fully supersonic wing is so much higher that the small benefit of a higher lift coefficient does still not make it attractive. The drag at those high lift coefficients is so high that any airplane will quickly decelerate to subsonic speed once it tries to reach those lift coefficients.


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Why do these aircraft in long term storage have air and power connections?
With the Covid-19 crisis many thousands of passenger aircraft have been put in storage. In this  Bloomberg article from July 2019 shows several aircraft in what appears to be storage with covers on engines and cockpit windows. They also appear to be connected to an electrical supply and the engines to some sort of compressor.
Here is a screen shot of the image:
And a link to a large size version of the full image.
Another link to a different photo of stored 737MAX with similar connections.
The Airbus website describes requirements for long term storage, but mentions no connections to air or electricity.
Why are these aircraft provided with air and power?

The cables may be ground connections.

Here's a Forbes story that adds detail to what is done to store 737MAXs but doesn't describe connection details in the above photos. https://www.forbes.com/sites/jeremybogaisky/2019/08/12/boeing-737-max-desert-storage/

howdy @DDuck , whoever threw together that page at Bloomberg, perhaps just added a "representative photo". It's unlikely that person specifically had detailed knowledge about whether these particular planes are in "long term" storage.  The planes may be in - just a random example - three-week storage while waiting for a decision to be made.  Jörg's answer seems to clarify the situation.

@Fattie True, but 6 months later you'd expect Flight Global to get it right.  Here is a different set of aircraft stored in a similar way https://www.flightglobal.com/air-transport/boeing-will-need-a-few-years-to-recapture-previous-737-max-production-rate-plans/136436.article

This link shows how Boeing is storing their 737MAXs and they don't have the extra connections. https://www.businessinsider.com/boeing-737-max-fills-storage-lots-2019-4

But seems important enough for other airlines to store them this way too. https://www.independent.co.uk/travel/news-and-advice/boeing-planes-737-max-jet-car-park-storage-aircraft-a8973726.html

right, it's an interesting question @DDuck !

Obviously it's the life support systems for the passengers while they await their delivery of lemon-scented paper napkins.

I thought they were for ventilation. Those things are going to smell horrendously if you keep them locked tight without ventilation.

Here is a plane spotter page for the Air Canada plane: https://www.planespotters.net/airframe/boeing-737-max-8-c-gelj-air-canada/ejjonj Its listed as not having been delivered, and is at Boeing Field in Seattle, so presumably is being stored by Boeing.

I don't feel any of the answers are 100% confident, but @JohnK will know...

I accept that some connections are ground wires. But you would think that there would be a standard procedure for ground wire. Why are they different? Why do some have them and not others?

I can see that conditioned air is useful. Things are stored in a cool, dry and dark environment for good reasons. The aircraft need to be looked after: tyres rotated, engines run, batteries charged to some manufacturer recommended schedule. Seats covered to prevent dust and solar damage. Engines and sensors covered to prevent birds nesting and other damage. Fluids adjusted to provide corrosion protection. Is the ducting / air hose connected the duct of the engine to conditioned air?  Why not for all aircraft in all locals?

Why do these aircraft in long term storage have air and power connections?

The photo is of 737MAX being stored in July 2019. Back then, airlines might still have hoped that this wouldn't be "long-term storage" at all!
Usually, airplanes being mothballed are stripped of corrosive / humidity-sensitive parts (e.g. the interior) as much as possible, stored in the dry desert, and it is considered acceptable if getting them back out of storage requires weeks if not months of refurbishment.
None of these three things seems to apply here. The photo doesn't look like it was taken in the desert, the airplanes are probably fully intact, and the airlines were hoping that with a simple software patch, they might be able to get them off the ground quickly again.
Therefore, they would have opted to, instead of preparing the airplanes for long-term storage, have them partially powered up, or use external air conditioning units. I would be willing to bet that those exact some planes are stored differently in July of 2020!

It turns out that they're not actually even owned by airlines, yet. According to airfleets.net, that aircraft in AC livery hasn't actually been delivered yet (as of summer 2020,) so I'd bet that's the case with all of them. This appears to be some of the MAXs stored by Boeing waiting for delivery pending the recertification of the MAX.

How long can you store an aircraft before it loses it's "new 'plane smell?"

@DDuck: Maybe that's what those air connections are for?

They probably have dehumidifiers inside to keep the air absolutely dry in there. This prevents any corrosion from occurring due to condensation or excess humidity.

I understand the requirement to keep things dry. A dehumidifier in the cabin (and engine) would make sense - but this requires someone to periodically drop by and empty the tank. The engines seem to be connected via pneumatic hose to some sort of unit - a compressor or heater -   this video for the CFM56 doesn't connect any unit to the engine.

@DDuck: They can just dump the water outside.

Let's see. You could use the aircraft's own air conditioning, you could use some sort of desiccant (silica gel etc) or you could flow dry air from somewhere - perhaps compressed air, that is cooled and dewatered or you could just use a chiller. Or you could use 100s of domestic dehumidifiers. You could also hang out in a region with dry air - perhaps somewhere really cold all the time. So I guess that there are two - cooling & chemical drying. (Some might argue compression, but there's cooling involved there too). Could heat everything too, but that's sometimes problematic.

@DDuck Industrial dehumidifiers exist, and you could just pipe a couple into the aircraft.

To cool and dehumidify the interiors
Except they don’t need to empty the tank every 6 hours.
As you probably know, when an aircraft gates, it shuts off all engines including the APU.  That means it relies on external power for electricity and HVAC.
The problem of hot interiors
Ever get in your car after it’s sitting in the hot sun, and it’s freakishly hot and you immediately start the A/C?  Try not doing that, close the door, leave the windows up and sit there for 5 minutes. You can’t.  It’s too darn hot. That’s why it’s so lethal when a baby is left in a car.  I’ve had PVC pipe, left in the hot car, actually bend into a pretzel.
That’s caused by the sun bearing down on the car.  It’s called “solar gain”. The same thing happens to railroad cars; that’s why railroad museums only have 2 kinds of cars: open-window, and air-conditioned.
For the auto industry to design interiors that can endure that for 20 years and not melt and bend like my PVC pipe, *is actually a really hard problem, and they spend billions on it. Obviously it’s the top priority in interior design.
Now turn the page to an airliner.   Exactly the same thing will happen due to solar load - except aviation interiors have a different top priority (safety and weight).  So they must compromise away automotive traits to get what they need.
Mind you, the best places to store airliners are dry and very hot - like the Mojave Desert or Tucson.  This makes the solar-load problem even worse.
So we have a) a vulnerable interior, b) very hot storage locations, and c) you can’t open the windows on an airplane.
That means you must run HVAC, or remove the interior, or lose it!
Damp interiors are just as much of a nightmare, as they will breed mold.  An unmaintained interior can accumulate moisture due to condensation: hot humid air leaks in during the day, then the humidity condenses in the cold night. Now you have liquid water where you did not expect.
Cooling (and dehumidifying) an airplane
Aircraft are already set up to take external sources for a few things: direct HVAC, compressed air and electricity. That’s so they can power down entirely at the gate for smog and fuel savings, and rely on shore-side equipment to keep the aircraft comfortable.
If they can hook up HVAC hoses (conditioned air) directly, that’s grand; however the airplane can make its own HVAC out of compressed air, thusly
The HVAC packs are designed to work on “bleed air”, compressed air drawn off the engines.  Shore-side compressed air works just as well.  The same thing happens whether shore-side or from engines: compressed air is very hot, and water-laden. It has the same air-mass:water-mass ratio as it did before it was compressed, so much more water per CC, and the hot air can hold that.
But when you cool compressed air, you reduce its capacity to hold moisture.  The moisture condenses at this point, and every compressor and intercooler has gear to contend with this (cheap home compressors have a drain on the bottom of the tank).
Now that the compressed air is cool, if you allow it to decompress, it becomes cooler still.  (This is just the reverse of the air heating up when compressed; it’s the poor man’s version of the freon cycle, same basic physics but not benefiting from the vapor-liquid enthalpy).
When you use an air-powered hand tool vigorously, it gets quite cold.
Since we’ve already wrung most of the water out of this air, when we decompress it, it comes out exceedingly dry compared to the air we started with at that same pressure.
Thus, we both air-condition and de-humidify the airplane in one stroke.

in a selection of articles found at the bottom of this page, none mentions connecting the aircraft to dry air. The suggestion is  to wrap them up somewhere hot and dry.

Barton says keeping an aircraft's cabin free of humidity is key. "[That way] it won't start to smell. That's what we worry about the most." https://www.cnet.com/features/parking-a-375-million-airplane-takes-more-than-just-locking-the-door/

@DDuck Because you don’t need to specify dry air; if you’re feeding conditioned air, it’s dry by nature because of the factors I discussed.  Nobody says “Hey, make sure that shore-side air is dry”.  As far as parking it at places like Mojave, it’s not quite that simple.  There are big temperature swings, and now you learn all about relative humidity.   That 110F air might be 20% RH, but when it cools at night to 50F, now it’s over 100% RH and condensing.

I lack the details, but its something to do with minimising the refurbishment time.  Its cheaper and easier to leave them on "low power" than to completely cold-store the aircraft.
You might find that periodically the engines are cycled in some way, the APU is started and run for a while, and the whole aircraft gets moved forward a few feet to roll the tyres over and minimise flat spots.
Cold-storing an aeroplane means about a hundred hours of ground-crew time, to change out all the oils, hydraulic fluids and coolant.  And its roughly the same level of effort required to reactivate a stored craft again. Contrast that to maybe an hour a week of effort to "warm-store" the aircraft, and this "hedging" becomes quite a good strategy for now.
It would be a fair bet that if air travel remains at current levels, some of these aircraft will be prepped for long-term storage, which may mean relocating them to one of the boneyard areas of the world, like Arizona, or the Australian outback.   At the moment, the jury is out on whether air travel will ever rebound to pre-pandemic levels.

Its the difference between winter-storing your petrol lawnmower, vs keeping it inside over the winter, if you want a more at-home similarity.

"this "hedging" becomes quite a good strategy for now" – Indeed. After all, the photo is of 737MAX in July 2019, back then airlines might still have hoped to have them back in the air within weeks.

I'd guess the white cart with the black hoses coming out provides high pressure air to start the engines periodically without having to start the APU. Its my understanding that the engines are started briefly once a week. The skinny light-colored cables look like ground cables, usually connected to a lug on the landing gear. I don't see anything resembling ground power cables, which would be much thicker and connect near the nose of the airplane.


text:
How can I design and build an aeroplane from scratch?
Let's say I want to build an aeroplane completely from scratch (not downloading some blueprints on the internet, I mean really designing it myself). The goal is to create a flyable aeroplane from scratch, that can safely fly.
What would I have to take into consideration and where are good resources for it? I don't want to depend on a wrong formula, and have the wing break off the aeroplane in mid-flight, because there was an error in the equation. So what resources are free (or cheap) and trustworthy?
I know, that the aeroplane should be reasonably aerodynamic and the wings should create lift. How do you test it, when you don't have a wind tunnel?
How can you compute the necessary wingspan and wing area and how do you test and analyze your design? They don't have to be that big, as you can see with the "jetman", who has a relatively small wing strapped to his back.
What programs would you use to run simulations? Are there free alternatives, that could be used instead and are they any good?
The design phase shouldn't cost much, except time. However, if there have to be certain precautions taken that cost something, that's OK.
What materials should be used (fiberglass, wood, carbon fiber, metal)?
How do I get the proof of airworthiness (on a design)? After this is done, I might actually go and build it myself.

You have too many questions in one post. Maybe you should try to breakdown each issue into its own question. And what do you expect from the plane? How heavy the load it must carry etc.

I would recommend building a kit airplane first, something somebody has proven as a design, like a Vans RV Series. After that, you'll have much more knowledge of how these things work. Given that it is pretty easy to kill yourself building your own airplane, I would highly recommend against going into this blind. Maybe take some Aerodynamics courses at the local college, do an A&P mentorship, etc. Get some experience first.

I agree, the question is extremely broad. But if you're interested, have a google for kit planes, such as Van's RVs.

This is a huge topic and I don't think we can give a single, good answer here. I don't know what country you're in but if you're serious about building any kind of aircraft yourself then if possible you should join the EAA and go along to your local chapter meetings. That's a great way to meet people who have built - and even designed - their own aircraft from scratch.

way too broad, and why flag the question as "faa regulations"? The FAA doesn't regulate design processes, they just have requirements for the end result of those design processes...

Take the example of Ed Swearingen: He never went to engineering school, but spent years working with airplanes, gradually moving from handling to repair to improving them. In the end, he was a successful self-employed consultant who helped with a number of airplane designs and created some of his own designs, too.
So here is what I propose to do:

Hang out at a local airport (ideally one with lots of hardware passing through the local repair shops)
Don't shy from getting your hands dirty and from asking questions until you are satisfied with the answer.
Try to find experienced engineers and work closely with them.

Do that for 10 years and you will be hard to beat as an aircraft designer. If you happen to attend University in Germany, be sure to become a member of one of their Akafliegs - that is the best start into an aviation engineering education.
If you have already some idea how your design should look like, build it as a model first. Models can give you valuable lessons in aerodynamics and flight mechanics.

...and the Swearingen Merlin and Metro lines as well!

@acpilot Yes, I know. The linked article mentions them, too. But this is incidental information for this answer, which I wanted to keep short, so I had too few words for all possible links.

I have voted to reopen as the accepted answer has missed a great resource for learning about and building aircraft:  The Experimental Aircraft Association, or EAA.  The OP should join immediately and download all the information he can, and also attend the EAA hands-on construction seminars, etc.  -Skip Miller


text:
How does VFR work in countries other than USA? What does hi and lo mean?
I saw that at https://skyvector.com/ the VFR sectional charts were available for the USA only. Do other countries use the same format for sectional charts?
Additionally What does Lo and Hi mean at this website?

I don't see any difference between the USA-Charts and the Charts in Europe.

As your question is currently written, it is too broad to produce any good answers. I could write books on "How do other countries manage their airspace?" - but that is not really the idea of this website. Please try to narrow down your question and be more specific.

"Sectional" charts per se are a US government product produced by NOAA, iirc. Doesn't mean that there aren't VFR charts for everywhere else, just that they aren't exactly the same product/format/nomenclature as the US VFR Sectional charts.

The "hi" and "lo" represent en-route high altitude and en-route low altitude.  The difference between the two is the transition altitude when switching from flying with reference to height to referencing altitude
The transition altitude varies from country to country (e.g. typically 18000 for the US and 3000 in the UK unless varied - 6000 in the London area for example) and can be found in various publications and on the en-route charts themselves.
The structure of airspace is consistent world-wide with some variations which are always marked on the relevant charts. There are far too many small variations to go into any detail here.
Finally, the charts themselves. Because the structure is consistent, the charts are also consistent although there are cosmetic differences such as the symbols used, colours used and certain pieces of useful information which may or may not be printed upon them.  The differences are easy enough to  learn quickly.  I've flown VFR in the  UK and the US and the charts look different, but are fundamentally the same. Within an individual country, charts may even differ cosmetically if the airspace is particularly busy when the chart makers may choose to omit less important information.

So can you fly VFR between USA and other countries if you are a VFR private pilot?

Subject to license requirements , e.g., yes. Easy within Europe, trickier in Asia and if going from Europe to the USA.


text:
How do I fill the PBN\ part in a Flight Plan Form?
Flight Plan Form Section 10 is the "Equipment" section, where one input whatever navigation or communication equipment on board. In addition, Section 18 is the "Other information" section, where you can add any supplemental information, some of it in relation to the aforementioned "Equipment" section.

My aircraft has every RNAV\RNP capabilities with indicators 1 through 10 (RNAV/RNP 10, RNAV 5, RNP 4, RNAV 2, RNAV/RNP 1). I need to use the "PBN\" indicator to detail PBN equipment capabilities. My question is how exactly?
In my case, should I file PBN\A1B2B4C2D2L1O2S1? Is it over the character limit? Is it actually necessary? Does it make sense?

This document provides the rules to limit the number of indicators, page 2: Filing Navigation Capability (Item 10 and Item 18 PBN/)"

Great info. Thanks.


text:
How is the A320neo life span calculated?
I read an article saying that the new Airbus A320neo life span is based on monthly cycles instead of hours or takeoff landing cycles, is this correct?
If so can I understand how it’s calculated based on monthly span?
Any external documents explaining this method will be much appreciated
Thanks

You need to post a link to the article if possible please.


text:
What were the common crew ranks on WWII US Navy flying boats and bombers?
I have been trying to figure this out for some time, but have not had much luck elsewhere. I have found info on USAAF bombers, and what ranks the crewmembers often had, but nothing for larger navy aircraft.
I know Pan-Am's Boeing 314 Clipper flying boat was operated by the US Navy for some time during WWII, but I don't know if the USN operated any heavy bombers or other large aircraft. If they did, what would the ranks of the crew (pilot/plane commander, co-pilot, flight engineer, bombardier, radioman, navigator, gunners, etc.) be?
Thanks in advance for any help.

Welcome to aviation.SE! If you don't get a good answer here you might also try history.SE, they have a lot of questions about military history.

The Navy did operate some large aircraft, notably the PB4Y-1 Liberator and PB4Y-2 Privateer, variants of the B-24 Liberator. This was a late-war addition, the first being delivered in 1944 with the majority being delivered after the war. It was difficult to find crew compositions - the best bet I had was searching for reports of crashes based off of this list, but the newspaper clippings I found did not mention any crews.
There was a post-WWII (1950) shoot-down of a Navy PB4Y-2 by the Soviets and the article does have the list of the crew members that went down, but without the crew positions (notes added based off of information here. This was an electronic intelligence flight, but the crew ranks would have been similar for the flight crew at least. Note: Navy enlisted have ranks and rates, rates being associated with their profession and as such will often be more difficult to determine where there is little information.

LT Howard W. Seeschaf

LT John H. Fette

LTJG Robert D. Reynolds

ENS Tommy L. Burgess (Ensign/O-1)

AT1 Frank L. Beckman (Avionics Electronic Technician)

AL3 Joseph J. Bourassa (Aviation Electronics Man)

AD 1 Joseph H. Danens (Aviation Machinist's Mate)

CT3 Edward J. Purcell (Communications Technician)

AN Joseph N. Rinnier (Airman)

AD 1 Jack W. Thomas (Aviation Machinist's Mate)


text:
During WWII, what did internal bomb bays and turret layout look like on flying boats?
I am writing an alternate WWII story, and I was wondering if you fine fellows on this site could help me. I am trying to make a fantasy bomber version of the USN Boeing C-98 Clipper, AKA the Boeing 314 Pan-Am Clipper flying boat. My idea is that the Navy ordered more C-98's as new builds after being impressed with the performance of the Pan-Am craft, and a bomber variant was developed.

So, were there any WWII era flying boats that had internal bomb bays? The German Blohm & Voss BV 238 is listed on Wikipedia as having 'wing bomb racks' and 'external racks'. The later jet powered 1960's Martin P6M Seamaster has an internal bay, but could that have been done back in WWII, or was the technology to keep the doors sealed when the craft was sitting on the water not up to par in the 1940's? Could they have used something similar to torpedo tube door seals from submarines?

Could something like this have been done with the hull of a modified C-98 design, or would it not be feasible with 40's tech?
Also, how would turrets be laid out on a flying boat? I'm thinking this craft is a long-range strategic bomber like the Flying Fortress, but I think belly turrets would probably be out of the question if this thing is going to land on the water. Would it have low down turrets on the sides of the fuselage to attempt to compensate for this?
Thanks in advance for any help.

For the bombs, the Short Sunderland used extendable racks. I think this aircraft is a good start to have a rough idea for your question.

https://en.wikipedia.org/wiki/Consolidated_PBY_Catalina#/media/File:US_Navy_090925-N-9860Y-006_A_PBY-6A_Catalina_drops_a_load_of_water_from_its_bomb-bay_doors_over_Crescent_Harbor.jpg would indicate that PBY Catalinas had bomb bay doors in WWII...

@JonCuster no those are doors added under an STC for water bombing.  WWII Catalinas/Cansos didn't have them.  They carried stuff on external racks under the wings.  That being said, there's nothing to say a flying boat bomber couldn't have had a bomb bay with belly doors like that.  They would just have to be heavy water tight doors.

@JohnK - Sounds reasonable. Even the homing torpedos for ASW were carried externally?

Yes the PBY had no provision for internal weapons storage. The aerial torpedoes were much shorter than naval ones and just look like elongated bombs.  If you wanted to drop bombs out the belly of the boat hull, best to incorporate that into the original design. Never heard of a flying boat that did that, only purpose built modern water bombers like the CL-215/435, etc.

@JohnK, do you think that in this hypothetical alternate universe, the Boeing C-98 design could be modified in such a manner to include bomb bay doors on a variant? It would be an added design feature on new builds, not conversions.

No reason you couldn't, although it would add a lot of weight.You would have to make the engines bigger, which would require more fuel, which would require even bigger engines to compensate for the extra weight of fuel, then ANOTHER power increase because of the weight gain of additional structure, and away you go on the aircraft engineering secondary effects merry-go-round! But seriously, for a fictional bomber, not a problem.


text:
How to correct CG on a not leveled aircraft?
I am tasked with weighing a fixed wing aircraft. the aircraft can not be leveled because the leveling points are damaged. therefor it is going to be weighed not leveled, an inclinometer will read a pitch angle and three scales will read the reaction from the LH and RH mains and nose. after the reactions are known and the pitch angle is know, how can I correct the cg for a leveled aircraft.

I might be asking a stupid question, but if you have an inclinometer that tells you the pitch, can't you level the aircraft by raising either the nose or the main gear until the inclinometer reads 0?

You have a problem because you would have to know where the vertical center of gravity is to be able to mathematically calculate a correction factor to apply to the weighing points.   The higher the vertical C of G is, the more rear weight bias you will get if the plane is nose-high from level, or front weight bias if nose-low.  How much to allow for?  You don't know.
When the plane is level, it doesn't matter where the vertical CG is.  You would be better off finding some other part of the structure that is aligned with the longitudinal axis from drawings or the maintenance manual, typically something like an upper fuselage longeron, to level the airplane.

Aassuming that the CoG is in the center line of the aeroplane, you can derive the leveled CoG if you use an inclonometer, but you would have to measure this at two different angles. Then simple high school triangulation would result in the CoG reading.
That is for a very accurate determination. If using only one measurement at an angle, there will be a measurement arror introduced by the vertical location of the CoG, proportional to the cosine of the inclonometer angle:

cos 0 (level) = 1.0, no error from vertical variation of the CoG.
cos 1° = 0.999985, an error of 0.015% times variation of vertical CoG distance.
cos 5° = 0.9962, an error of 0.38% times variation of vertical CoG distance.

Not huge. I don't know what the required precision is for determination of the CoG, and what the upper/lower possible vertical CoG limits are; these would be used in calculating the tolerance of the single CoG measurement at a known angle.


text:
Is the 777X actually the newest Boeing plane?
I don't think the 777X is actually the newest Boeing plane (in april 2020), since it's only a new variant of a previous Boeing plane. So the actual newest plane would belong to the 787, since it's the newest plane. If that makes sense? Can anyone answer why Google says the 777X is the newest Boeing plane?

The answer depends on how you define "newest".

Related: Is the Boeing 777X being certified as a derivative of the 777 Classic?

@StephenS: As Bianfable's link shows, there is an official answer to that. We can argue whether that's the right answer, especially in the light of the 737-MAX disasters.

While the 777X is a derivation from the older 777 Classic family of airplanes, it is, in fact a brand new airplane, similar to the difference between the 747-8 and the 747 Classic line or the F/A-18E/F Super Hornet compared with the F/A-18A-D series. Based on that and the rollout date of the 777X, it would be BCA’s latest airplane.

Minor nitpick: the 777 Classic only refers to the 777-200, -200ER and -300 models. The second generation 777-200LR, -200F and -300ER are not Classic any more. The 777X is now the third generation, arguably with much larger differences compared to the first and second generations.

Fair enough.....

One can refer to general types, variants of a type, and individual machines or airframes of a variant/type. Any example of each may be distinguished from other types/variants/machines as a different plane. Which of these is indicated by "plane" depends on context. For example de Havilland DH.88 Comet G-ADEF was a newer plane than DH.88 Comet G-ACSS. Or, the Spitfire Mk. VIII was actually a newer plane than the Mk. IX. But which was the newer plane, the Comet (which flew first) or the Spitfire (which was designed first)? The context is unambiguous in all cases, you know what I mean. Since the Google context is equally unambiguous, there is no problem.


text:
Is the war pilot obligated to fly the same plane daily or must he change the plane according to every required mission?
Can the pilot change his plane, or can he fly in any plane, obediently, to the same plane as the one trained on it?

Welcome to AviationStackExchange. In order to better your chances of getting a fact based answer, please limit your questions to those that are not opinion based. Also, narrow your questions to specifics. Details will provide clarity for the answerers.

Hi Haitham, do you mean that the pilot flies the same plane type (like Airbus 320), but just changes between different individual planes, or do you mean planes of different type (like Airbus 320 / 350)? Or maybe even planes of whole different category or manufacturer (like Airbus/Bombardier)?

Thanks for the edit, Haitham. I just saw it. I’ve already answered your original post to the best of my ability. Hopefully, a current military pilot can further expound upon it for your specific military interest.

a "war pilot"? do you mean a military?  If so, which kind? fighter? bomber? transportation? trainer?

Of which type of pilot are you asking:

Student
Military
Private (hobbyist)
Corporate
Airline

I will be using the term licensed to loosely mean certificated, current, and proficient with the proper endorsements and documentations.
The short answer is no. They are not obliged/obligated to fly the same aircraft. The pilot can choose to fly in any aircraft they want. They will more than likely choose an aircraft that fits their mission.
The long answer depends on the mission. This might determine if the pilot gets the opportunity to fly at all. Or, what “mission” (job, employer, flight school, opportunity) they choose to seek. But, all aircraft fly a differently from each other. In the same make and model, the differences may be slight. In the same category and class, the differences may be very challenging. In different categories, classes, and types, the differences may be too great to overcome without specific training.
Students:
Most instructors will want their students to stick to one type of aircraft for their initial training (first 35-80 hours). That does not mean it will be the exact same aircraft. Large schools may have several identical aircraft of the same make, model, and avionics (when possible). The students will be expected to fly whichever aircraft is available at the time of the lesson. Although, the instructor can endorse the student to fly solo in any aircraft the instructor feels the student can handle on their own. This is essential in developing habits, muscle memory, and structure.
After initial training, the student (then private pilot) is then only limited to flying the same category and class of aircraft in which he/she was trained. Although he student can seek training in another category and/or class. I flew both single engine land airplanes, and helicopters.
Private (hobbyist):
A private pilot can fly any aircraft for which they are properly licensed. The license will only stipulate category and class of aircraft for which a type rating is not required, type rating, and other flight category ratings. Type ratings are usually required for large and/or turbine aircraft. Some other ratings are based on flight categories (VFR vs IFR). There are some restrictions based on medical requirements. And, some flight categories will require specific endorsements (tailwheel, high altitude, high performance, complex, aerobatic, etc.) They can also fly in aircraft for which they are not properly licensed if a properly licensed Pilot-in-Command is also flying at the controls.
There is a class of hobbyist pilots who are very limited in the type of aircraft that they fly. These pilots need endorsements for any aircraft outside of their specific category, class, or type of aircraft.
As a practical matter, a hobbyist pilot may fly several aircraft based on availability. There are flying clubs and aircraft rental companies that give pilots access to aircraft as they wish. Provided the pilot has the proper license and is able to perform adequately on a flight evaluation. I regularly fly several different Piper Cherokee varieties, Cessna 150/2, 172 and 182 varieties, SportCruisers, Robinson R-22s, etc. Availability and cost both play a factor.
Corporate & Airline:
Generally, these types of pilots will hold type ratings in specific makes and models of aircraft. Since it is a pretty large expense to maintain currency of these type ratings, which ones they will be able to exercise might be limited. Which specific aircraft they fly within their license requirements will be up to the needs of their employer at that time. They may fly different aircraft day by day, or even flight by flight on the same day.
These pilots can still exercise the privileges of their private pilot certificate and many do. In which case, they are free to fly any aircraft for which they are licensed. Their employer may limit them to only fly on a for-hire basis for the employer, solely. That does not limit them from flying as a hobbyist.
Military:
The military is going to determine which aircraft the pilot flies. It is the military after all. What the pilot flies is going to be based on the needs of the military. The pilot can make requests. But, being in the military means that the pilot has volunteered (in the U.S.) to do what they tell him/her to do.
Generally, that is going to be mission and budget based. The military will train the pilot for a specific type of aircraft, for a specific type of mission. If the pilot or aircraft does not suit the mission, they use a different pilot. If the military chooses to use the original pilot, they send them back to training for that specific aircraft, for that specific mission.
Both the trained pilot and the aircraft they are flying are very valuable assets. They are expensive tools that the military will handle with care (sort of). Mistakes cost lives and money.
What this means from a practical sense is that a pilot will not flip-flop between types of aircraft. There would have to be a very compelling reason to do so (like change of duty station or aircraft inventory). For the most part, the pilot will be assigned a specific individual aircraft unless the mission dictates otherwise. After all, it is their weapon. They must be proficient with it.
Think of it this way. You are not obliged/obligated to drive a certain car. You drive the car that fits your needs and budget. But then again, you are not obliged/obligated to work for an employer who may require you to drive a certain company vehicle.

Not all nation's military pilots are assigned an individual aircraft. Take the RAAF for example. The assigned aircraft is determined by a lot of external factors including lifing, configuration of external fuel tanks, serviceability, etc. Just because their name is on the jet, doesn't mean anything. Birds are swapped between units to suit the mission so it might not even have the right squadron markings.

@Craig - Thanks. Your comment is duly noted. Assigned is a very tricky term. For instance, an infantryman will be assigned a rifle. That does not mean the rifle is theirs to keep forever. Depending on the mission, they could be assigned a different weapon system all together. Or, may even be assigned a weapons system from a different unit. That weapon is their responsibility until signed back in to the armory. But, anyone could be called upon to use that weapon in the heat of combat. Whatever the military needs. Not necessarily by individual choice.

Combat aircraft often were assigned to single crew for their tour of duty, which is how all the bombers could have names and unique images on them and fighters the name of pilot and marks of their aerial victories. But the same was never true of cargo aircraft when e.g. on The Hump (India-China air bridge) they were approaching 20 hour a day utilization towards the end. That means the aircraft were almost constantly flying or loading and unloading when not being overhauled and constantly changing crews as one crew only flew 60–70 hours a month (750 flight hours in a year).

@JanHudec - Thanks, Jan. I’m assuming the OP is asking more about pilots jumping from plane to plane rather than one plane having multiple pilots. Something like a pilot flying a fighter/interceptor like an F-16 on Monday to secure the airspace. Then jumping in an A-10 on Tuesday to provide troops ground support. Or, even a transport aircraft like a C130 or C17, if the mission required it. I would imagine even changing to a different type of weapons system on the same airframe would require some amount of training. I could be wrong, though.

@DeanF., I don't think they needed type ratings for C47 and C46 back then, just multi-engine endorsement, but these days they certainly have some kind of type rating for most types just like civilians do.


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What does "Raven" [phonetic] means when used by ATC?
What is the meaning of "Raven" [phonetic] heard in use at Reagan National Airport?  Most recently heard: The ATC will say "proceed direct raven" or "direct raven maintain" whatever altitude; or "direct raven; raven at 6,000."  I've looked in every ATC/Pilot glossary I can find, but nothing.  Have not heard at other airports, not even Dulles or BWI in the Washington metro area.  A military pilot friend thinks it is an enroute, departure, approach or holding fix, which he says would be specific to one airport.  Can anyone tell me exactly what we are hearing [an acronym?] and if this is the meaning?

What value does the word "phonetic" add to this question?

RAVNN (Pronounced Raven) is the name  of a waypoint in Maryland. From the FAA Fixes / Waypoints directory

RAVNN MARYLAND BAL*C*174.00/22.98 OTT*C*070.89/12.17
  ENO*C*250.66/53.40 DCA*D*106.56 38-48-15.9900N 076-31-04.9100W

38°48'15.9900N 76°31'04.9100W(Google Maps link) is east of Washington.

The nearby city of Baltimore has an American football team called the Ravens, so Raven is probably a waypoint somewhere in the Baltimore area.

My favorite waypoints will always be ITAWT, ITAWA, PUDYE, TTATT, and the missed approach hold over IDEED.

RAVNN is a waypoint on the RAVNN6 STAR (page 1, page 2) for KBWI and surrounding airports, which is handled by Potomac Approach.

Generally, the idea is that a waypoint has a five letter or six letter code that is

unique (within the region)
easy to remember
easy to pronounce as a word
hard to confuse

In this case, the code of the waypoint is RAVNN, but it is pronounced "raven", because that is much faster to say, much easier to remember, and just as easy to understand as "Romeo Alpha Victor November November". The idea is that even if you've never been to the area before and have never heard the waypoint pronounced before, when the controller says "raven", you can immediately understand that she is talking about RAVNN. Imagine, the controller says "Romeo Alpha Victor November November" and you are looking at your approach plate and then try to remember "Wait, was it Romeo Alpha at the beginning or Alpha Romeo?"
Additionally, when there is a standard approach using multiple waypoints, the waypoints are sometimes chosen in such a way that they "tell a story", e.g. using words from a well-known children's rhyme, poem, song, proverb, quote, Bible verse, etc.
For example, a fictional approach could go along waypoints QUOTH RAVNN NVMOR or HAMLT TOBEE ORNOT or something like that. WEEEE WLLLL NEVVR FORGT SEP11 is a real one that actually exists, going into Washington.


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Does bi-wings create essentially double the uplift as single wings?
This puzzles me a bit, and I cannot find the answer anywhere.
Does bi-wings create essentially double the uplift as single wings?

Therenis no single answer. As a general rule a biplane will generate less than twice the lift from one wing, but exactly how much lift it generates will depend on the exact configuration and aerofoil in use. It will also generate more drag.

Related: https://aviation.stackexchange.com/questions/21845/can-biplane-or-triplane-designs-be-revived-with-modern-materials

Related: how-is-the-lift-generated-by-a-number-of-out-of-plane-staggered-wings-calculated

You might precise in your question how you want to compare both. How do your biplane and your monoplane wingspan and chord differ (if they differ)? if you keep the same wingspan and chord, you double the wing area (not taking into account the fuselage width nor wings position). Do they fly at the same speed?

In general, no it does not.
If by bi-wings you mean a biplane then the airflow above the lower wing and the airflow below the upper wing interfere with each other and lift is lost. The loss is kept acceptable if the gap is at least 1.25 times the wing chord, but it is still maybe 20% depending on the design. The advantage of the biplane is that it is light and compact, which at slow speeds can more than compensate for the loss of lift.
If by bi-wings you include tandem wings, then the wake of the fore wing creates a disturbed airflow over the aft wing, reducing its efficiency. This can be minimised by mounting the fore wing low and the aft wing high, but that introduces the risk of superstall at high angles of incidence. The advantage of the tandem layout is that it allows a large range of positions for the centre of gravity, giving high operational flexibility.

Nothing is 100% efficient, so it's probably not TWICE... Given the same airfoil and chord, you're probably going to get close to the same that you would get if you had a mono-wing that was twice as long.  The struts that go between the wings are going to add some drag.  The shorter wingspan of the biplane though will likely give a faster roll rate, assuming that the ailerons are placed the same distance from the fuselage and are the same size in both the mono-wing and biplane.


text:
What happened to Flight Sao Paulo TAM 402 flight?
I have watched a MAYDAY documentary (season 15 episode 10) and it appeared they had a reverse thrust problem.
Can someone please explain to me what really happened in simpler terms?
I have watch the scenes multiple times but don't understand what had happened. Was it pilot error or something else?

Did you read https://en.wikipedia.org/wiki/TAM_Transportes_A%C3%A9reos_Regionais_Flight_402? It is written in fairly layman's terms. Is anything still not clear after reading it?

Agreed, this is well explained by the Wikipedia article. Not sure if that merits closing the question though? There's nothing we can really add to that summary IMO.

Maybe I need to start checking out Wikipedia, I wasn't certain the information was accurate. Thanks guys.

@Asynchronous in that case you'd better ask about what you think is not accurate. Wikipedia is sourced so that you can read sources by yourself. In general, the TV show mayday is made for TV, i.e. it is made to be visually impressive and dramatic (emphasizing spectacular facts) and time constraint (not developing some significant contributing factors)

If I may paraphrase the Wikipedia article on the accident...
The Fokker 100 aircraft had a safety feature to throttle back an engine in the case its thrust reverser deployed during climb or cruise. Unfortunately, there was no indicator or alarm to notify the crew of the unintended thrust reverser deployment.
On the accident takeoff, a faulty switch cause uncommanded thrust reverser deployment. The throttle was retarded automatically. The crew, not knowing why the throttle had moved, manually overrode it. This left the plane with insufficient climb power.
Also, the crew had no training in this scenario, as training had been deemed unnecessary by the aircraft manufacturer.
So I don't think you can simply blame this accident on pilot error.

Yeah they were pushed into brain lock pretty quickly. On the CRJ200 you can't mistake what's going on.  It has a spring jack back on the engine that basically slams the thrust lever back with quite a bit of force if the reverser unlocks (it has to overcome the friction of a long teleflex cable), and if your thumb is in the way it'll likely be dislocated.  We were trained to only push on the thrust lever handles with the heel of the hand, keeping the thumb on top.


text:
How to take into account wind in aerodynamic forces balance?
I'm trying to make a basic simulation for horizontal drift of a falling object due to wind. I need the force balance so that I can find out the acceleration of the object from the wind.
The object is initially dropped with zero horizontal velocity with the only force acting on the object being forces applied by the wind which is a constant velocity. I would like to use an observer on the ground as a reference frame. The projectile will be dropped directly above an observer and will accelerate in the direction of the wind until reaching steady state (velocity of the wind).
I want measure how far the projectile moves in the horizontal direction while it falls to the ground. I am getting confused on how forces are applied to the object.
The way I originally thought the only force was wind pressure applied over the surface area of the object.
$F_{wind} = \frac{1}{2}\rho v^2 A$
I was unsure however, if there was any help from the drag force. Does the drag force add to the force from wind pressure? Is the wind force just the drag force with a different name?
EDIT: Adding some clarification to the problem setup.

If you want to assume that the object is initially released with zero groundspeed, and you are interested in analyzing the initial acceleration, then you need to make that clear. Speaking of "drift" but not "acceleration" tends to suggest you are looking at a steady-state condition; see xxavier answer.

If you do want to consider acceleration, then you need to consider all aerodynamic forces.  You can either deal in terms of airspeed, or in terms of ground speed plus wind speed.  They are the same.  This may possibly be of some use to you: see all associated links as well: https://physics.stackexchange.com/questions/491600/flight-time-of-spherical-bullet-fired-horizontally-versus-dropped-vertically-e/491771#491771

Re initial comment: yes of course you do mention acceleration as well as drift.  Need some clarification as to initial conditions, and reference frame.

Cutting to the chase, is the object being dropped from a freely drifting balloon, or from a tower, or from an airplane, or do you wish to be able to consider 3 cases?  Actually now that my answer addresses all 3 I guess technically you need to be careful about edits but still curious what you had in mind.

Technically the edit may be construed to invalidate some parts of my answer, but in this case I don't mind and I feel it is a good edit. If someone complains about the edit invalidating the other answer, you (or anyone) could add "and case b, what if the object were dropped from a free balloon".  It would seems silly to suggest that a question must be left in an ambiguous state so as not to invalidate an existing answer.

In this case, you use the weight of the object and its drag coefficient, as if it was SLOWING DOWN to a steady state in the wind field (V= 0, relative to wind speed). Compare a beach ball to a lead sinker to start your modelling.  The math is the FINAL step.

I suggest you ask this in Physics.se as well.

It's ok here, the OP is essentially holding a ball up in a wind tunnel, then letting go of it.  If it isn't too dense and not very aerodynamic, the person below will be fine.

Additional response to edited question: object is dropped with an initial groundspeed of zero: the only forces present as object falls are gravity and aerodynamic drag.  Drag is a function of airspeed, which has a vertical component as well as a horizontal component.  If you use the airmass reference frame, the ONLY significance of wind is that 1) the initial condition is that airspeed equals wind speed, and 2) during the time the object is falling there will be some horizontal translation between the airmass reference frame and the ground reference frame, which will affect the final answer when converted back to the ground reference frame.  See notes below, and links at end, about not being able to solve for vertical and horizontal accelerations independently of each other.

Read on for more (some content was originally aimed at a broader version of the question)  :
Cutting to the chase, is the object being dropped from a freely drifting balloon, or from a tower, or from an airplane?  I.e. is the horizontal airspeed initially zero, or not?  Dropping from an airplane is more like dropping from a tower than dropping from a freely drifting balloon, because the initial horizontal component of airspeed is not zero.
Once an object has accelerated to freely move with the wind, the horizontal component of airspeed is zero, so the wind exerts no force on the object. This makes calculations easier.  In theory, if the initial horizontal component of airspeed is non-zero, it will take a infinite amount of time for the horizontal component of airspeed to fall all the way to zero, just as it takes an infinite amount of time to fully achieve the vertical terminal velocity.  In practice, after a few tens of seconds the horizontal airspeed will probably be very close to zero.
If the object is initially released with zero groundspeed, then the horizontal component of the airspeed vector is initially not zero, but rather is equal to the wind speed.   It turns out that this has an effect on the object's vertical acceleration as well as the object's horizontal acceleration, even if the body is a perfect sphere!  (See links below for more.)
If the object is dropped from an airplane, wind or no wind, the situation is essentially the same as if the object is dropped from a tower in wind.  The key point is that the horizontal component of airspeed is not zero at the instant of release.
If horizontal as well as vertical airspeed, force, and acceleration components are present at the instant of release, then you need to take care to properly consider the true magnitude and direction of the net aerodynamic force acting on the object.  You need to write your equations in terms of the airspeed vector, which also is equal to the ground speed vector (including the vertical component) plus the wind speed vector.  You can't treat drag due to wind speed, drag due to horizontal ground speed, and drag due to vertical falling speed as independent entities, because drag is dependent on airspeed squared, and all these components of motion contribute to airspeed.
Ultimately it's up to you whether you want to work in terms of the airmass reference frame (which moves with the wind) or the ground reference frame, so long as your equations appropriately deal with the x, y, and z components of the airspeed vector.  It will generally be much easier to work in terms of the airmass reference frame, and view the ground as moving carpet down below, like one of those airport people-mover beltways.  Just bear in mind that IF the object is released with zero groundspeed, then the initial condition is that the horizontal airspeed equals the wind speed.  IF the object is dropped from a freely drifting balloon, then the initial condition is that airspeed is zero.  IF the object is dropped from an airplane, then the initial condition is that the dropped object's airspeed equals the airplane's airspeed.  Regardless of which is true, once the appropriate initial condition is set, forget about the wind, except for checking at the end to see how much the ground moved relative to the airmass reference frame, during the time of fall.
In other words, if the object is released from an aircraft with a known airspeed vector, and the airmass (wind field) is uniform, then you can ignore the wind while you do your calculations in terms of airspeed, and then you can add on the "drift" relative to the ground due to the translation of the airmass reference frame relative to the ground during the time of fall.
It appears from your question that you hoped to be able to compute horizontal acceleration components independent of vertical acceleration components.  In any case where the object's initial horizontal airspeed is not zero, that's not going to work.  Just as the horizontal airspeed at any instant affects the rate of change of vertical airspeed, so too does the vertical airspeed at any instant affect the rate of change of horizontal airspeed.  See links below for more.
On the hand, if you are just dropping objects from a freely drifting balloon in a uniform wind field, then you can ignore most of this answer.  In that case, horizontal airspeed, force and acceleration are zero.
These links should be of some use to you: see all associated links as well:
https://physics.stackexchange.com/questions/176513/calculating-wind-force-and-drag-force-on-a-falling-object/176515#176515
https://physics.stackexchange.com/questions/491600/flight-time-of-spherical-bullet-fired-horizontally-versus-dropped-vertically-e/491771#491771

Thank you for the in depth response. So when I look at the object in the wind frame I am still a little confused on how the force is applied. Is the only force (other than gravity) drag due to wind (in both the x and y axis)?

See last bit added in italics near end.  Not so much wind per se, but airflow.

Now moved to top of answer

Ok, so when I calculate the drag with respect to the airflow am I able to then break each forces into x and y axes at that point? From there I could have the projectile decelerate with respect to the the airflow until the horizontal axis has the same velocity as the wind which in this frame would be 0 velocity and the vertical axis is equal to the force of gravity. Is there still a concept that I am not grasping?

Sounds basically right except that the vertical SPEED will continue to increase till terminal velocity is reached; the vertical FORCE is equal to weight minus vertical component of drag throughout the whole time.  Got to run, consider asking Physics SE for more details?

Future edit; "In that case, horizontal airspeed, force and acceleration are zero." -- would be more clear to say "In that case, the horizontal components of airspeed, force and acceleration are all zero."

The falling object moves within the mass of air, and suffers no horizontal forces at all... For a ground observer, it drifts with the wind...

But if the object was dropped from a fixed point, which I think is what the questioner is talking about, it will start out with its relative wind off of perpendicular, starting at 90 degrees at the moment of release and eventually becoming 0 degrees.  So it sees a side force that diminishes to 0 once it's moving laterally at the same speed as the wind.  The question relates to the lateral acceleration phase.

Downvoted because this is not true.  If you dropped a bowling ball from shoulder height would it "drift with the wind" from the perspective of a ground observer?  Density, time, windspeed, and possibly other factors all play into how much a falling object deflects from vertical.

@MichaelHall the answer is obviously taking the perspective of dropping a bowling ball from a freely drifting balloon, etc.  It could use some clarification as to that point.

@quiet flyer - "Obviously" and "could use some clarification" don't really go together.  It is obvious, or it is not.  You of course are free to presume what you want, but the question says nothing about the object being dropped from a platform already moving at the same speed as the wind.  And if it was, a dense object like a bowling ball would eventually overcome the wind drift of the platform (think hot air balloon) and take a path much closer to vertical so that it would not strike the ground directly below the drifting platform from which it was dropped.

Point being, a dense object will not "drift with the wind".  Inertia from the force of gravity will overcome the side force of the wind.

@MichaelHall - point taken about "obviously", but I definitely strongly disagree that a bowling ball dropped from a balloon, in a uniform wind field, will not impact directly below the balloon.  A ribbon streamer attached to the ball would stream straight up vertically throughout the fall, as well.  The ball will never "feel" any sideways wind at all in such a case.

I can't do the math to prove my point, but I have a common sense gut feel that it not the case.  The balloon just has a heck of a lot more surface area for the wind to affect while the bowling ball free falls.  Maybe a smart engineer will step in with a good answer...

@quiet flyer - To borrow from Roberts example, picture standing with your back to a 20mph wind.  In one hand is a beach ball, in the other a lead sinker.  If you drop them at the same time they will not both "drift with the wind" equally, the beach ball will travel much further down range.  Now picture that you've rigged them together, and have a way to remotely trip the lead to fall just after the ball starts drifting.  The lead will still hit the ground closer to the release point.  Again, no math needed for me to know in my gut what the outcome will be.

@MichaelHall -- sure.  But that's not the same as dropping them from a freely drifting balloon.  See my previous two comments.

@MichaelHall -- could be grounds for another question here, about dropping items from a freely drifting balloon. This answer could be copied over to that new question as sell.


text:
What is the force to change the pitch of a variable pitch propeller?
At the moment I am struggling with the problem that I do have an idea how to calculate this force by using the blade element theory and going over a whole propeller blade in order to calculate the torque inside the blade. I need this torque in order to calculate the force necessary for changing my pitch inflight. Is the blade element theory the correct way to calculate this?

Source: Nelson, Wilbur C.: Airplane Propeller Principles (John Wiley & Sons, 1944).
Also I do lack information regarding the airfoil data. Is there a good estimate on how high the coefficient of torque will be? Is there a good airfoil database for propellers online?
The assumption that cm=-1/4*ca does not work, as profiles on propellers are not even plates.

depends on the propeller, on the speed you're flying, on the arm available to apply the force (same force, but twice the arm gives twice the torque)

Edited question to clarify
Just to get it correct: I am not looking for the torque my engine has to deliver to get the propeller spinning, but I am searching for the torque my blades generate, in order to calculate the force for an electric servo/hydraulic mechanism I need to change my pitch in flight.
As this is a variable pitch propeller, the speed I am flying should be of lower importance, since my angle of attack (and thus my coefficient of torque) as well as the rotational speed are way higher.
I do hope for a general method, but in my application case it will be a plane with Ma<0.3

Per this post, the X-Plane flight simulator uses blade element theory on the prop disk, which gives the drag and therefore torque.

This doesn't answer the question, but this link provides great info on how a Constant Speed Propeller and it's Governor work.  I
don't know how much engine oil pressure is needed to change the pitch, or what the formula might be for 2,3,4 blae propellors.http://www.boldmethod.com/learn-to-fly/aircraft-systems/how-a-constant-speed-prop-works/

Are you scratch building a variable pitch propeller?!

In a well-designed propeller the hinge axis is very close to the line connecting the centers of pressure, so the aerodynamic pitch moment is rather small. The main force is friction; note that the centrifugal pull of the blades at the hub will put a considerable load on the blade bearings, so friction goes up with rotation speed. Regular propellers have plain bearings; if you know the mass of the blade, the rotation speed and the coefficient of friction, you can calculate the breakaway torque of one blade.
Since propeller blades have some (but not much) camber, the center of pressure moves forward with increasing angle of attack. This will drive the blade away from a medium angle of attack; in other words, the aerodynamic moment is destabilizing the propeller pitch.

Paging @PeterKämpf to the chat room, paging Peter Kämpf to the white courtesy chat room!

Did I get something wrong with aerodynamics? With increasing angle of attack the coefficient of torque (cm) should decrease, not increase (assuming we are in the linear area),  as you stated. Thus I should get a stabilizing moment for higher angles of attack and not a destabilizing one.

@Lumis: That entirely depends on the axis around which you measure the torque. If you use the quarter chord, the coefficient should ideally be constant. If you place the axis of rotation at roughly one third of chord (what propeller designers normally do), the coefficient has a positive (instable) gradient over AoA.

Is there some kind of literature or source with examples on the axis of rotation? Maybe even something I could use for citation?

@Lumis: The root of a variable pitch propeller blade is cylindrical, and the center of this cylinder is the axis of rotation. Maybe https://www.google.com/patents/US2496169 will do.